Method for performing a surgical procedure and a cannula for use in performing the surgical procedure

ABSTRACT

A method of performing a surgical procedure on a body includes providing a cannula having a tubular structure with first and second tubular portions defining first and second passages for receiving surgical instruments. The second tubular portion is inserted inside the body and the first tubular portion is inserted so that the first tubular portion extends from an exterior of the body to inside the body. The second tubular portion expands to increase the cross-sectional area of the second passage in the second tubular portion while the second tubular portion is inside the body. The cross-sectional area of the first passage in the first tubular portion is maintained. The first tubular portion has a first thickness and the second tubular portion has a second thickness different than the first thickness.

This application is a divisional application of U.S. patent applicationSer. No. 10/435,730, filed May 9, 2003 now U.S. Pat. No. 6,811,588,whichis a divisional application of U.S. patent application Ser. No.09/772,605, filed Jan. 30, 2001 now U.S. Pat. No. 6,800,084, which is acontinuation-in-part of U.S. patent application Ser. No. 09/137,335,filed Aug. 20, 1998, now U.S. Pat. No. 6,187,000, issued Feb. 13, 2001.

TECHNICAL FIELD

The present invention is directed to a method for performing a surgicalprocedure on a body and a cannula for receiving surgical instrumentsduring the surgical procedure.

BACKGROUND OF THE INVENTION

Endoscopic surgical techniques allow a surgical procedure to beperformed on a patient's body through a relatively small incision in thebody and with a limited amount of body tissue disruption. Endoscopicsurgery typically utilizes a tubular structure known as a cannula whichis inserted into a small incision in the body. The cannula holds theincision open and serves as a conduit extending between the exterior ofthe body and the local area inside the body where the surgery is to beperformed.

Due to the relatively small size of the passage into the body which isdefined by the cannula, certain surgical procedures, such as posteriordisectomies and procedures using steerable surgical instruments, havebeen difficult to perform using endoscopic techniques.

SUMMARY OF THE INVENTION

The present invention is a method for performing a surgical procedure ona body and a cannula for receiving surgical instruments during thesurgical procedure. In one embodiment, the method of performing thesurgical procedure on the body includes providing the cannula having atubular structure with first and second tubular portions defining firstand second passages for receiving surgical instruments. The secondpassage is a continuation of the first passage.

The cannula is inserted through an incision in the body. The secondtubular portion is inserted inside the body and the first tubularportion is inserted into the incision so that the first tubular portionextends from an exterior of the body to inside the body. The secondtubular portion of the cannula expands to increase the cross-sectionalarea of the second passage in the second tubular portion while thesecond tubular portion is inside the body. The cross-sectional area ofthe first passage in the first tubular portion is maintained.

The first tubular portion of the cannula has a first thickness measuredin a direction perpendicular to inner and outer surfaces of the firsttubular portion. The second tubular portion has a thickness measured ina direction perpendicular to inner and outer surfaces of the secondtubular portion. The first thickness is different than the secondthickness.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomeapparent to one skilled in the art to which the present inventionrelates upon consideration of the following description of the inventionwith reference to the accompanying drawings, wherein:

FIG. 1 is an exploded perspective view of a surgical cannula constructedin accordance with a first embodiment of the present invention, thecannula being shown in an expanded condition;

FIG. 2 is a perspective view of the cannula of FIG. 1 with parts removedfor clarity, the cannula being shown in a contracted condition;

FIG. 3 is a schematic end view showing the cannula of FIG. 1 in theexpanded position;

FIG. 4 is a rollout view of a part of the cannula of FIG. 1;

FIG. 5 is a schematic sectional view of the cannula of FIG. 1 during asurgical procedure;

FIG. 6 is a perspective view of a part of a surgical cannula constructedin accordance with a second embodiment of the present invention, thecannula being shown in an expanded condition;

FIG. 7 is a perspective view of the part of the cannula of FIG. 6, thecannula being shown in a contracted condition;

FIG. 8 is a perspective view of a part of a surgical cannula constructedin accordance with a third embodiment of the present invention, thecannula being shown in an expanded condition; and

FIG. 9 is a sectional view of a portion of the cannula of FIG. 8 showinga rivet connecting a first tubular portion to a second tubular portion.

DESCRIPTION OF THE INVENTION

The present invention is directed to a method for performing a surgicalprocedure on the body of a patient and a cannula for receiving surgicalinstruments during the surgical procedure. The present invention isapplicable to a variety of surgical procedures in which endoscopicsurgical techniques are used.

FIG. 1 illustrates a cannula 10 constructed according to a firstembodiment of the present invention. The cannula 10 is a tubularstructure 12 centered on an axis 14. The tubular structure 12 defines apassage 16 through the cannula 10. Surgical instruments are insertedinto the body during endoscopic surgery through the passage 16.

The tubular structure 12 comprises a first tubular portion 20 and asecond tubular portion 40 attached to the first tubular portion. Thefirst tubular portion 20 is preferably made of a length of stainlesssteel tubing, but could alternatively be made of another suitablematerial such as a radiolucent material. The first tubular portion 20has a proximal end 22 and a distal end 24. Parallel cylindrical innerand outer surfaces 26 and 28, respectively, extend between the ends 22,24 of the first tubular portion 20. The inner surface 26 defines a firstpassage portion 30 of the passage 16 through the cannula 10. The firstpassage portion 30 has a diameter D1 which is preferably in the rangefrom 10 mm to 20 mm or approximately 0.4 inches to approximately 0.8inches.

The second tubular portion 40 of the tubular structure 12 is attached tothe distal end 24 of the first tubular portion 20. The second tubularportion is preferably made from stainless steel, but could alternativelybe made from another suitable material such as a radiolucent material.

As best seen in the rollout view of FIG. 4, the second tubular portion40 comprises an arcuate segment 42 of sheet stock. The arcuate segment42 includes first and second arcuate edges 44 and 46, respectively, andfirst and second planar edges 48 and 50, respectively. The first andsecond planar edges 48 and 50 are rolled in an overlapping manner toform the tubular configuration of the second tubular portion 40.

When the second tubular portion 40 has been rolled into its tubularconfiguration, the first and second arcuate edges 44 and 46 defineoppositely disposed first and second ends 60 and 62 (FIGS. 1 and 2),respectively, of the second tubular portion. The first and second ends60 and 62 are connected by a central portion 64. The first end 60 of thesecond tubular portion 40 is attached to the distal end 24 of the firsttubular portion 20 by a single suitable fastener, such as a rivet 66.The rivet 66 extends through two aligned apertures 68 (FIG. 4) at thefirst end 60 of the second tubular portion 40. The first end 60 of thesecond tubular portion 40 is pivotable about the rivet 66.

The second tubular portion 40 includes parallel inner and outer surfaces70 and 72 (FIGS. 1 and 2), respectively, extending between the first andsecond ends 60 and 62. The inner surface 70 defines a second passageportion 74 of the passage 16 through the cannula 10 which extends as acontinuation of the first passage portion 30 in the first tubularportion 20.

An arcuate slot 80 is formed in the second tubular portion 40 andextends between the inner and outer surfaces 70 and 72 of the secondtubular portion. The arcuate slot 80 extends along a curvilinear path inthe central portion 64 of the second tubular portion 40 toward thesecond end 60 of the second tubular portion. The arcuate slot 80 has afirst terminal end 82 located in the central portion 64 of the secondtubular portion 40. A second terminal end 84 of the arcuate slot 80 islocated adjacent the intersection of the second arcuate edge 46 and thefirst planar edge 48 of the arcuate segment 42.

A suitable guide member, such as guide pin 90, is attached to the innersurface 70 of the second tubular portion 40 adjacent the intersection ofthe second arcuate edge 46 and the second planar edge 50. In the tubularconfiguration of the second tubular portion 40, the guide pin 90 islocated in the arcuate slot 80 and is movable along the curvilinear pathof the arcuate slot. A washer 92 is secured to an inner end of the guidepin 90 to retain the guide pin in the arcuate slot 80.

The second tubular portion 40 of the tubular structure 12 is expandablefrom a contracted condition shown in FIG. 2 to an expanded-conditionshown in FIG. 1. In the contracted condition, the guide pin 90 islocated in the first terminal end 82 of the arcuate slot 80 in thesecond tubular portion 40 and the second passage portion 74 defined bythe second tubular portion is cylindrical in shape. The second passage74 has a generally constant diameter D2 (FIGS. 2 and 3) which isapproximately equal to the diameter D1 of the first tubular portion 20.Thus, the cross-sectional area of the second passage portion 74 at thesecond end 62 of the second tubular portion 40, which is a function ofthe diameter D2, is approximately the same as the cross-sectional areaat the first end 60 of the second tubular portion and is approximatelythe same as the cross-sectional area of the first passage portion 30 inthe first tubular portion 20.

In the expanded condition, the guide pin 90 is located in the secondterminal end 84 of the arcuate slot 80 in the second tubular portion 40and the second tubular portion has a conical configuration. At thesecond end 62 of the second tubular portion 40, the second passageportion 74 has a diameter D3 (FIG. 3) which is larger than the diameterD2 of the second passage portion at the first end 60. Preferably, thediameter D3 of the second passage portion 74 at the second end 62 of thesecond tubular portion 40 is 40% to 80% greater than the diameter D2 ofthe second passage portion at the first end 60. Thus, in the expandedcondition, the cross-sectional area of the second passage portion 74 atthe second end 62 of the second tubular portion 40, which is a functionof the diameter D3 , is greater than the cross-sectional area of thesecond passage portion at the first end 60 of the second tubularportion.

The cannula 10 includes an outer layer 100 (FIG. 1) for maintaining thesecond tubular portion 40 of the cannula in the contracted condition. Itis contemplated that other suitable means for maintaining the secondtubular portion 40 in the contracted condition could be employed. Inaccordance with a preferred embodiment of the present invention, theouter layer 10 comprises a section of plastic tubing 102 which is heatshrunk over both the first and second tubular portions 20 and 40 to holdthe second tubular portion in the contracted condition.

In addition, a loop of nylon string 104 for tearing the heat shrinktubing 102 is wrapped around the heat shrink tubing so that it extendsboth underneath and on top of the tubing. An outer end 106 of the string104 extends beyond the tubing 102.

The cannula 10 further includes an actuatable device 110 for expandingthe second tubular portion 40 from the contracted condition to theexpanded condition. In accordance with a preferred embodiment of thepresent invention, the actuatable device 110 comprises a manuallyoperated expansion tool 112. The expansion tool 112 resembles a commonpair of scissors and has a pair of legs 114 pivotally connected to oneanother. The expansion tool 112 includes a frustoconical end section 116formed by a pair of frustoconical halves 118. Each of the frustoconicalhalves 118 extends from a respective one of the legs 114 of theexpansion tool 112. It is contemplated that other suitable means forexpanding the second tubular portion 40 toward the expanded conditioncould be employed, such as an inflatable balloon (not shown).

During an endoscopic surgical procedure, the cannula 10 is inserted inthe contracted condition through an incision into the body of a patient.The second tubular portion 40 is inserted inside the body. The firsttubular portion 20 is inserted into the incision so that the firsttubular portion extends from an exterior of the body to inside the body.

The outer end 106 of the string 104 is then manually pulled on by thesurgeon. Pulling on the string 104 tears the heat shrink tubing 102which is then removed from the cannula 10 by the surgeon. With the heatshrink tubing 102 removed, the second tubular portion 40 of the cannula10 is thereby released for expansion toward the expanded condition.

Next, the expansion tool 112 is inserted into the passage 16 in thecannula 10 until the frustoconical end section 114 is located at thesecond end 62 of the second tubular portion 40. The legs 114 of theexpansion tool 112 are manually separated, causing the frustoconicalhalves 118 to separate also. As the halves 118 separate, a radiallyoutwardly directed force is exerted on the inner surface 70 of thesecond tubular portion 40 by the halves 118, causing the second tubularportion to expand toward the expanded condition.

Under the force of the expanding expansion tool 112, the guide pin 90slides from the first terminal end 82 of the arcuate slot 80 to thesecond terminal end 84 of the arcuate slot to permit the expansion ofthe second tubular portion 40. The expansion tool 112 can be rotatedabout the axis 14 to ensure that the second tubular portion 40 of thecannula 10 is completely expanded to the expanded condition. Theexpansion tool 112 is then collapsed and removed so that one or moresurgical instruments (indicated schematically at 120 in FIG. 5) can bereceived through the cannula 10 and inserted into a patient's body 130.

The expandable second tubular portion 40 of the cannula 10 provides asignificantly larger working area for the surgeon inside the body 130within the confines of the cannula. As a result, the simultaneous use ofa number of endoscopic surgical instruments, including but not limitedto steerable instruments, shavers, dissectors, scissors, forceps,retractors, dilators, and video cameras, is made possible by theexpandable cannula 10.

A cannula 150 constructed according to a second embodiment of thepresent invention is illustrated in FIGS. 6-7. The cannula 150 includesa tubular structure 152 centered on an axis 154. The tubular structure152 defines a passage 156 through the cannula 150. Surgical instrumentsare inserted into the body during endoscopic surgery through the passage156.

The tubular structure 152 (FIG. 6) comprises a first tubular portion 160and a second tubular portion 180 attached to the first tubular portion.The first tubular portion 160 is preferably made of a length ofstainless steel tubing, but could alternatively be made of anothersuitable material, such as a radiolucent material. The first tubularportion 160 has a proximal end 162 and a distal end 164. Parallelcylindrical inner and outer surfaces 166 and 168 extend between the ends162, 164 of the first tubular portion 160. The first tubular portion 160has a thickness measured perpendicular to the surfaces 166 and 168 inthe range of 0.02 inches to 0.04 inches or approximately 0.5 mm toapproximately 1.0 mm.

The inner surface 166 defines a first passage portion 170 of the passage156 through the cannula 150. The first passage portion 170 has adiameter d1 which is preferably in the range from 10 mm to 20 mm orapproximately 0.4 inches to approximately 0.8 inches. The inner surface166 has a non-reflective coating 174. The non-reflective coating 174reduces glare on any video image produced by a video camera insertedthrough the passage 156. It is contemplated that the inner surface 166may not have the coating 174.

The second tubular portion 180 (FIG. 6) of the tubular structure 152 isattached to the distal end 164 of the first tubular portion 160. Thesecond tubular portion 180 is preferably made from stainless steel, butcould alternatively be made from another suitable material, such as aradiolucent material.

The second tubular portion 180 includes an arcuate segment 182 of sheetstock. The arcuate segment 182 includes first and second arcuate edges184 and 186. The arcuate segment 182 also includes a first planar edge188 and a second planar edge extending between the arcuate edges 184 and186, which is not shown in FIG. 6. The first and second planar edges arerolled in an overlapping manner to form the tubular configuration of thesecond tubular portion 180. When the second tubular portion 180 has beenrolled into its tubular configuration, the first and second arcuateedges 184 and 186 define oppositely disposed first and second ends 200and 202 of the second tubular portion. The first and second ends 200 and202 are connected by a central portion 204. The first end 200 of thesecond tubular portion 180 is attached to the distal end 164 of thefirst tubular portion 160 by a suitable fastener, such as a screw 206and nut 208 threaded on the screw. It is contemplated that the secondtubular portion 180 could be connected to the first tubular portion 160by a rivet. The screw 206 extends through two aligned apertures 240 atthe first end 200 of the second tubular portion 180. The first end 200of the second tubular portion 180 is pivotable about the screw 206.

The second tubular portion 180 includes parallel inner and outersurfaces 212 and 214 extending between the first and second ends 200 and202. The inner surface 212 defines a second passage portion 216 of thepassage 156 through the cannula 150 which extends as a continuation ofthe first passage portion 17.0 in the first tubular portion 160. Thesecond tubular portion 180 has a thickness measured perpendicular to thesurfaces 212 and 214 in the range of 0.003 inches to 0.005 inches orapproximately 0.075 mm to approximately 0.125 mm. The inner surface 212has a non-reflective coating 218. The non-reflective coating 218 reducesglare on any video image produced by a camera inserted through thepassage 156. It is contemplated that the inner surface 212 may not havethe coating 218.

An arcuate slot 220. (FIG. 6) is formed in the second tubular portion180 and extends between the inner and outer surfaces 212 and 214 of thesecond tubular portion. The arcuate slot 220 extends along a curvilinearpath in the central portion 204 of the second tubular portion 180 towardthe end 184 of the second tubular portion. The arcuate slot 220 has afirst terminal end (not shown) located in the central portion 204 of thesecond tubular portion 180. A second terminal end 224 of the arcuateslot 220 is located adjacent the intersection of the second arcuate edge186 and the planar edge 188 of the arcuate segment 182.

A guide member or screw 230 is attached to the inner surface 212 of thesecond tubular portion 180 adjacent the intersection of the secondarcuate edge 186 and the planar edge (not shown). It is contemplatedthat a guide pin could be used instead of the screw 230. In the tubularconfiguration of the second tubular portion 180, the guide member 230 islocated in the arcuate slot 220 and is movable along the curvilinearpath of the arcuate slot.

The second tubular portion 180 of the tubular structure 152 isexpandable from a contracted condition, shown in FIG. 7, to an expandedcondition, shown in FIG. 6. In the contracted condition (FIG. 7), theguide member 230 is located in the first terminal end (not shown) of thearcuate slot 220 in the second tubular portion 180 and the secondpassage portion 216 defined by the second tubular portion is cylindricalin shape. The second passage 216 has a generally constant diameter d2which is approximately equal to the diameter d1 of the first tubularportion 160. Thus, the cross-sectional area of the second passageportion 216 at the second end 202 of the second tubular portion 180,which is a function of the diameter d2, is approximately the same as thecross-sectional area at the first end 200 of the second tubular portionand is approximately the same as the cross-sectional area of the firstpassage portion 170 in the first tubular portion 160.

In the expanded condition (FIG. 6), the guide member 230 is located inthe second terminal end 224 of the arcuate slot 220 in the secondtubular portion 180 and the second tubular portion has a conicalconfiguration. At the second end 202 of the second tubular portion 180,the second passage portion 216 has a diameter d3 which is larger thanthe diameter d2 of the second passage portion at the first end 200.Preferably, the diameter d3 of the second passage portion 216 at thesecond end 202 of the second tubular portion 180 is 40% to 80% greaterthan the diameter d2 of the second passage portion at the first end 200.Thus, in the expanded condition, the cross-sectional area of the secondpassage portion 216 at the second end 202 of the second tubular portion180, which is function of the diameter d3, is greater than thecross-sectional area of the second passage portion at the first end 200of the second tubular portion.

The cannula 150 includes an outer member (not shown) for maintaining thesecond tubular portion 180 of the cannula in the contracted condition.It is contemplated that other suitable means for maintaining the secondtubular portion 180 in the contracted condition could be employed. Inaccordance with the present invention, the outer member may be similarto the layer 100 shown in FIG. 1 and include a section of plastic tubingwhich is heat shrunk over both the first and second tubular portions 160and 180 to hold the second tubular portion in the contracted condition.In addition, a loop of nylon string (not shown) for tearing the heatshrink tubing is wrapped around the heat shrink tubing so that itextends both underneath and on top of the tubing. An outer end of thestring extends beyond the tubing.

During an endoscopic surgical procedure, the cannula 150 is inserted inthe contracted condition through an incision into the body of a patient.The second tubular portion 180 is inserted inside the body. The firsttubular portion 160 is inserted into the incision so that the firsttubular portion extends from an exterior of the body to inside the body.

The outer end of the string is then manually pulled on by the surgeon.Pulling on the string tears the heat shrink tubing which is then removedfrom the cannula 150 by the surgeon. With the heat shrink tubingremoved, the second tubular portion 180 of the cannula 150 is therebyreleased for expansion toward the expanded condition.

Next, the expansion tool 112, shown in FIG. 1, is inserted into thepassage 156 in the cannula 150 until the frustoconical end section 114is located at the second end 202 of the second tubular portion 180. Thelegs 114 of the expansion tool 112 are manually separated, causing thefrustoconical halves 118 to separate also. As the halves 118 separate, aradially outwardly directed force is exerted on the inner surface 212 ofthe second tubular portion 180 by the halves 118, causing the secondtubular portion to expand toward the expanded condition. Under the forceof the expanding expansion tool 112, the guide member 230 slides fromthe first terminal end of the arcuate slot 220 to the second terminalend of the arcuate slot to permit the expansion of the second tubularportion 180. The expansion tool 112 can be rotated about the axis 154 toensure that the second tubular portion 180 of the cannula 150 iscompletely expanded to the expanded condition. The expansion tool 112 isthen collapsed and removed so that one or more surgical instruments canbe received through the cannula 150 and inserted into a patient's body.

The thickness of the second tubular portion 180 allows the secondtubular portion to deform as the second tubular portion expands. As thesecond tubular portion 180 expands and engages tissue in the body, thetissue resists expansion of the second tubular portion. The secondtubular portion 180 must deform slightly to prevent the second tubularportion from being damaged while expanding.

The expandable second tubular portion 180 of the cannula 150 provides asignificantly larger working area for the surgeon inside the body withinthe confines of the cannula. As a result, the simultaneous use of anumber of endoscopic surgical instruments, including but not limited tosteerable instruments, shavers, dissectors, scissors, forceps,retractors, dilators, and video cameras, is made possible by theexpandable cannula 150.

A cannula 250 constructed according to a third embodiment of the presentinvention is illustrated in FIGS. 8-9. In the embodiment of theinvention illustrated in FIGS. 6-7 the tubular portions 160 and 180 areconnected by a screw 206 and nut 208 and the guide member is a screw230. In the embodiment of the invention illustrated in FIGS. 8-9 thetubular portions are connected by a rivet and the guide member is arivet. The cannula 250 is generally similar to the cannula 150 shown inFIGS. 6-7. Accordingly, only the rivets will be described in detail.

The cannula 250 (FIG. 8) includes a tubular structure 252 centered on anaxis 254. The tubular structure 252 defines a passage 256 through thecannula 250. The tubular structure 252 includes a first tubular portion260 and a second tubular portion 280 attached to the first tubularportion. The first tubular portion 260 has a proximal end 262 and adistal end 264. Parallel cylindrical inner and outer surfaces 266 and268 extend between the ends 262, 264 of the first tubular portion 260.The inner surface 266 defines a first passage portion 270 of the passage256 through the cannula 250. The inner surface 266 could have anon-reflective coating (not shown).

The second tubular portion 280 (FIG. 8) of the tubular structure 252 isattached to the distal end 264 of the first tubular portion 260. Thesecond tubular portion 280 includes an arcuate segment 282 of sheetstock. The arcuate segment 282 includes first and second arcuate edges284 and 286. The arcuate segment 282 also includes a first planar edge288 and a second planar edge extending between the arcuate edges 284 and286, which is not shown in FIG. 8. The first and second planar edges arerolled in an overlapping manner to form the tubular configuration of thesecond tubular portion 280.

When the second tubular portion 280 has been rolled into its tubularconfiguration, the first and second arcuate edges 284 and 286 defineoppositely disposed first and second ends 300 and 302 of the secondtubular portion. The first and second ends 300 and 302 are connected bya central portion 304. The first end 300 of the second tubular portion280 is attached to the distal end 264 of the first tubular portion 260by a rivet 306. The rivet 306 extends through two aligned apertures 340at the first end 300 of the second tubular portion 280. The first end300 of the second tubular portion 280 is pivotable about the rivet 306.

The rivet 306 (FIGS. 8 and 9) has a first portion 308 and a secondportion 310. The first portion 308 has a shaft 312 extending from a head314. The shaft 312 extends through the apertures 340 in the tubularportion 280 and the head 314 engages the inner surface 266 of the firsttubular portion 260. A cylindrical opening 316 extends through the shaft312 and the head 314.

The second portion 310 of the rivet 306 has a shaft 318 extending from ahead 320. The shaft 318 extends into the opening 316 in the firstportion 308 of the rivet 306 and the head 320 engages the second tubularportion 280. The shaft 318 of the second portion 310 extends into theopening 316 in the first portion 308 to connect the first and secondportions of the rivet 306 and pivotally-connect the second tubularportion 280 to the first tubular portion 260.

The second tubular portion 280 (FIG. 8) includes parallel inner andouter surfaces 322 and 324 extending between the first and second ends300 and 302. The inner surface 322 defines a second passage portion 326of the passage 256 through the cannula 250 which extends as acontinuation of the first passage portion 270 in the first tubularportion 260. The inner surface 322 could have a non-reflective coating(not shown).

An arcuate slot 330 is formed in the second tubular portion 280 andextends between the inner and outer surfaces 322 and 324 of the secondtubular portion. The arcuate slot 330 extends along a curvilinear pathin the central portion 304 of the second tubular portion 280 toward theend 284 of the second tubular portion. The arcuate slot 330 has a firstterminal end (not shown) located in the central portion 304 of thesecond tubular portion 280. A second terminal end 334 of the arcuateslot 330 is located adjacent the intersection of the second arcuate edge286 and the planar edge 288 of the arcuate segment 282.

A rivet 336 is attached to the inner surface 322 of the second tubularportion 280 adjacent the intersection of the second arcuate edge 286 andthe planar edge (not shown). It is contemplated that a guide pin couldbe used instead of the rivet 336. In the tubular configuration of thesecond tubular portion 280, the rivet 336 is located in the arcuate slot330 and is movable along the curvilinear path of the arcuate slot. Therivet 336 extends through a washer 338 to retain the rivet in thearcuate slot 330.

The rivet 336 is generally similar to the rivet 306 and, therefore, willnot be described in detail. The rivet 336 has a first portion 342 and asecond portion 344. The first portion 342 has a shaft 346 extending froma head 348. The shaft 346 extends through the slot 330 and the head 348engages the washer 338. A cylindrical opening 350 extends through theshaft 346 and the head 348.

The second portion 344 of the rivet 336 has a shaft 352 extending from ahead 354. The shaft 352 extends into the opening 350 in the firstportion 342 of the rivet 336 and the head 354 engages the outer surface324 of the second tubular portion 280. The shaft 352 extends into theopening 350 to connect the first portion 342 of the rivet 336 to thesecond portion 344.

The second tubular portion 280 of the tubular structure 252 isexpandable from a contracted condition to an expanded condition, shownin FIG. 8. In the contracted condition the rivet 336 is located in thefirst terminal end (not shown) of the arcuate slot 330 in the secondtubular portion 280 and the second passage portion 326 defined by thesecond tubular portion is cylindrical in shape. The second passageportion 326 has a generally constant diameter which is approximatelyequal to the diameter of the first tubular portion 260. Thus, thecross-sectional area of the second passage portion 326 at the second end302 of the second tubular portion 280 is approximately the same as thecross-sectional area at the first end 300 of the second tubular portionand is approximately the same as the cross-sectional area of the firstpassage portion 270 in the first tubular portion 260.

In the expanded condition (FIG. 8), the rivet 336 is located in thesecond terminal end 334 of the arcuate slot 330 in the second tubularportion 280 and the second tubular portion has a conical configuration.At the second end 302 of the second tubular portion 280, the secondpassage portion 326 has a diameter which is larger than the diameter ofthe second passage portion at the first end 300. Thus, in the expandedcondition, the cross-sectional area of the second passage portion 326 atthe second end 302 of the second tubular portion 280 is greater than thecross-sectional area of the second passage portion at the first end 300of the second tubular portion.

During an endoscopic surgical procedure, the cannula 250 is inserted inthe contracted condition through an incision into the body of a patient.The second tubular portion 280 is inserted inside the body. The firsttubular portion 260 is inserted into the incision so that the firsttubular portion extends from an exterior of the body to inside the body.

Heat shrink tubing is removed from the cannula 250 by the surgeon. Withthe heat shrink tubing removed, the second tubular portion 280 of thecannula 250 is thereby released for expansion toward the expandedcondition. Next, the expansion tool 112, shown in FIG. 1, is insertedinto the passage 256 in the cannula 250 until the frustoconical endsection 114 is located at the second end 302 of the second tubularportion 280. The legs 114 of the expansion tool 112 are manuallyseparated, causing the frustoconical halves 118 to separate also. As thehalves 118 separate, a radially outwardly directed force is exerted onthe inner surface 312 of the second tubular portion 280 by the halves118, causing the second tubular portion to expand toward the expandedcondition. Under the force of the expanding expansion tool 112, therivet 336 slides from the first terminal end of the arcuate slot 330 tothe second terminal end 334 of the arcuate slot to permit the expansionof the second tubular portion 280. The expansion tool 112 is thencollapsed and removed so that one or more surgical instruments can bereceived through the cannula 250 and inserted into a patient's body. Theexpandable second tubular portion 280 of the cannula 250 provides asignificantly larger working area for the surgeon inside the body withinthe confines of the cannula. As a result, the simultaneous use of anumber of endoscopic surgical instruments including but not limited tosteerable instruments, shavers, dissectors, scissors, forceps,retractors, dilators, and video cameras, is made possible by theexpandable cannula 250.

It is contemplated that the cannula 10, 150, and/or the cannula 250described herein could be the centerpiece of an endoscopic surgical kitwhich would include an assortment of surgical instruments designedand/or selected for use with the cannula.

From the above description of the invention, those skilled in the artwill perceive improvements, changes and modifications. Suchimprovements, changes and modifications within the skill of the art areintended to be covered by the appended claims.

1. A method for providing minimally invasive access to a spinal locationof a patient, said method comprising: inserting an access device throughthe skin of a patient, the access device having a first access portionhaving a first outer surface and a first inner surface at leastpartially defining a passage for receiving a plurality of surgicalinstruments, the access device having a second access portion attachedto said first access portion, the second access portion having a secondouter surface and a second inner surface at least partially defining thepassage for receiving at least one surgical instrument; positioning theaccess device in the patient such that a proximal portion thereof isoutside the patient and a distal portion is near the spine; inserting anexpander device into the access device; actuating the expander device tocause opposing portions of the distal portion of the access device tomove in a direction generally transverse to a longitudinal axis of thepassage, thereby moving the access device from a contracted condition toan expanded condition, causing the outer surface of the distal portionto retract the tissue surrounding the spine to provide a surgical fieldfor the spinal surgical procedure; pivoting the proximal portion of theaccess device from a first position to a second position adapted toenhance the visibility and access of the surgical field; and insertingan instrument through the passage to perform a procedure on the spine.2. The method of claim 1, wherein the first access portion comprises aportion of the proximal portion.
 3. The method of claim 1, wherein thesecond access portion comprises a portion of the distal portion.
 4. Themethod of claim 3, wherein the first access portion comprises a portionof the proximal portion.
 5. The method of claim 4, wherein said accessdevice further comprises a fastener and the pivoting is provided aboutsaid fastener.
 6. The method of claim 5, wherein the first accessportion comprises a first hole and the second access portion comprises asecond hole, the fastener extending through the first hole and thesecond hole.
 7. The method of claim 6, wherein the fastener comprises arivet.
 8. The method of claim 1, wherein the second access portioncomprises an arcuate segment that is rolled such that first and secondopposite ends overlap in an area where the first end extends over thesecond end.
 9. The method of claim 8, wherein the overlap area isreduced by actuating the expander device.
 10. The method of claim 9,wherein said access device further comprises a fastener and the pivotingis provided about said fastener.
 11. The method of claim 10, wherein thefirst access portion comprises a first hole and the second accessportion comprises a second hole, the fastener extending through thefirst hole and the second hole.
 12. The method of claim 10, wherein thefastener comprises a rivet.
 13. The method of claim 1, furthercomprising forming an incision in the skin of the patient and insertingthe access device through the incision.
 14. The method of claim 1,further comprising: advancing a first surgical instrument through thepassage to the spinal location; and inserting a second surgicalinstrument into the passage while the first surgical instrument is inthe passage.
 15. The method of claim 1, wherein the passage has a widthin the second access portion that is greater than about 14 mm.
 16. Themethod of claim 1, wherein the passage has a width in the second accessportion that is between about 14 mm and about 36 mm.
 17. The method ofclaim 1, wherein actuating the expander device in the access devicecauses the second access portion to be shaped like a portion of a cone.18. The method of claim 1, wherein the first access portion comprises atubular portion.
 19. The method of claim 18, wherein the second accessportion is coupled with the tubular portion and extends distallytherefrom.
 20. The method of claim 1, wherein the cross-sectional areaof a portion of the passage in the distal portion is approximatelyconstant before and after actuating the expander tool.
 21. The method ofclaim 1, wherein the access device further comprises a first edge and asecond edge, the first edge and second edge cooperating to limitmovement of the distal portion of the access device.
 22. The method ofclaim 21, wherein the access device comprises an arcuate slot and aguide member disposed in said arcuate slot, the first edge defining anedge of the slot and the second edge defining a portion of the guidemember.
 23. A method for providing minimally invasive access to a spinallocation of a patient, said method comprising: inserting an accessdevice through the skin of a patient, the access device having a firstaccess portion having a first outer surface and a first inner surface atleast partially defining a passage for receiving a plurality of surgicalinstruments, the access device having a second access portion attachedto said first access portion, the second access portion formed of anarcuate segment of sheet stock having first and second opposite ends,the sheet rolled into a tubular shape with overlapping first and secondends, the sheet having a second outer surface and a second inner surfaceat least partially defining the passage for receiving at least onesurgical instrument; inserting the access device through an incision inthe patient such that a proximal portion thereof is outside the patientand a distal portion is near the spine; inserting an expander deviceinto the access device actuating the expander device to cause opposingportions of the distal portion of the access device to moved in adirection generally transverse to a longitudinal axis of the passage,thereby moving the access device from a contracted condition to anexpanded condition causing the outer surface of the distal portion toretract the tissue surrounding the spine to provide a surgical field forthe spinal surgical procedure; pivoting the proximal portion of theaccess device from a first position to a second position adapted toenhance the visibility and access of the surgical field; and insertingan instrument through the passage to perform a procedure on the spine.24. A method for providing minimally invasive access to a spinallocation of a patient, said method comprising: inserting an accessdevice through the skin of a patient, the access device having a firstaccess portion having a first outer surface and a first inner surface atleast partially defining a passage for receiving a plurality of surgicalinstruments, the access device having a second access portion attachedto said first access portion, the second access portion having a secondouter surface and a second inner surface at least partially defining thepassage for receiving at least one surgical instrument, the secondaccess portion having an arcuate slot and a guide member disposed in thearcuate slot; positioning the access device in the patient such tat aproximal portion thereof is outside the patient and a distal portion isnear the spine; inserting an expander device into the access deviceactuating the expander device to cause the guide member of the accessdevice to move from a first terminal end of the slot toward a secondterminal end of the slot to move opposing portions of the distal portionof the access device in a direction generally transverse to alongitudinal axis of the passage, thereby moving the access device froma contracted condition to an expanded condition, thereby increasing across sectional area of the passage and causing the outer surface of thedistal portion to retract the tissue surrounding the spine to provide asurgical field for the spinal surgical procedure; pivoting the proximalportion of the access device from a first position to a second positionadapted to enhance the visibility and access of the surgical field; andinserting an instrument through the passage to perform a procedure onthe spine.